As long as a pilgrim doesn’t omit any rukn of Hajj,  it should be clear that Hajj is valid, insha‘ Allah, but one has to offer sacrificial animals because of omitting the obligatory duties of Hajj.

Elaborating on this, Sheikh Ibn `Uthaymeen, a prominent Saudi Muslim scholar, (may Allah shower mercy on his soul), issued the following: For each of any obligatory rites missed, one has to offer a sacrifice to be slaughtered in Makkah and its meat should be distributed to the poor because whoever omits one of the obligatory duties of Hajj has to offer a sacrifice to be slaughtered in Makkah and its meat should be distributed to the poor.

Allah Almighty knows best.